Electrical plug connector



DCC 25, 1956 F. G. HEUNEMAN ELECTRICL PLUG CONNECTOR F11/Qd Jan. 11.1954 United States Patent O ELECTRICAL PLUG CONNECTOR Fred G.-Heuneman,Livingston, N. J. Application January 11, 1954, Serial No. 403,216 2Claims. (cl. 339-74) This invention relates to an improved electricalplug connector for detachable insertion into a wall outlet or likereceptacle, whereby to connect the circuit wires of an appliance cord orcable to an electric service circuit in which the outlet or receptacleis included.

The invention has for an object to provide a plug connector havingmovable contact blades and manipulatable means to control the contactblade movements whereby, upon operative insertion of the plug in a walloutlet or like receptacle, said contact blades will substantiallyinterlock with the latter against accidental separation therefrom.

The invention has for a further object to provide a plug connectorhaving a pair of spaced contact blades pivotally mounted within the plugbody or casing to project outwardly from the latter; said contact bladesbeing spring urged to swing-about their supporting pivots so as .todivergently spread their outwardly projecting portions, when the sameare entered in a wall outlet or like receptacle, whereby to both forcesaid contact blades into good and iirm electrical engagement withinternal contact elements of the outlet or receptacle and to secure theplug to the outlet or receptacle against accidental pulling away anddisconnection therefrom; manipulatable means being provided for swinginglthe contact blades against the tension of their spreading spring meansto normal positions parallel one to the other, so as to facilitateentrance thereof into or withdrawal thereof from the outlet orreceptacle, as the case may be.

The above and other objects will be understood from a reading of thefollowing description of an illustrative embodiment of the invention asshown in the accompanying drawings, in which:

Fig. l is a face view of the electrical plug according to thisinvention, showing the movable contact blades as normally positioned inparallel relation for insertion into or withdrawal from an outlet orother receptacle; Fig. 2 is a view similar to that of Fig. 1 but with acover plate of the plug body or casing removed to disclose the internalparts of the structure; Fig. 3 is a view similar to that of Fig. 2, butshowing the contact blade control means positioned to -allow springurged spread of contact blades; Fig. 4 is a transverse Ihorizontalsection, taken on line 4 4 in Fig. 3; and Fig. 5 is another transversehorizontal section, taken on line 5-5 in Fig. 3.

Similar characters of reference are employed in the above describedviews, to indicate corresponding parts.

Referring to the drawings, the plug connector comprises a two part bodyformed by a main casing and 2,775,744 Patented Dec. 25, 1956 ICC ance tobe served by the plug connector, can be entered. Leading outwardly fromthe chamber 13 through the bottom end of the plug body is an opening ormouth 17.

Pivotally supported in connection with the plug body are a pair oflaterally spaced apart metallic contact blades 18 and 19, each formed toprovide an upper internal arm 20 lying within the plug body chamber 13,and a lower external arm 21 to project through the bottom opening ormouth 17 exteriorly of the plug body. Each contact blade 18 and 19 isprovided intermediate its arms 20 and 21 with a hinging knuckle 22projecting from its outer face, through which extends a pivoting pin 23that is suitably atiixed to the plug body, preferably by imbedding theends thereof respectively in the casing face Wall and in the cover platefor bridging extension between these parts within the chamber 13 (seeFig. 4), and in location above but adjacent 4to said bottom opening ormouth 17 of the plug body. As thus pivotally supported, said contactblades can rock about ,their fulcrums in plane parallel to the faceplanes of the plug body.

Engaged between respective side edge walls of the casing 10 and theupper arms 20 of the respective contact blades 18 and 19 are compressionsprings 24. The side edge walls` of the casing 1i) are provided withmeans by which said springs 2.4 are footed or purchased to exerciseyieldably in swinging thrust against the upper arms 2o of the contactblades, with resultant divergent relative spreading of the exteriorlyprojecting external arms 21 of said contact blades; said footing meanspreferably comprising sockets 25 in which outer ends of said respectivesprings are seated..

Formed in connection with the free ends of the upper arms 20 of therespective contact blades 13 and 19 are internally screw-threadedperforate ears 26 tted with binding screws 27 by which respectiveconductors 28 and 29 of the cord or cable 16 can be electricallyconnected with said respective contact blades 18 and 19.

Movably mounted within the internal chamber 13 of the plug casing 10,intermediate the upper arms 20 of the contact blades 18 and 19, so as tobe vertically slidable in said casing toward and from an alignedposition relative to and between the pivotal fulcrums of said contactblades, is a manipulatable blade control member 30,

a cover or face plate 11 which is removably secured to which islpreferably of -circular cross-section. Projecting from at least one endand preferably from each end of said control member 30, is a lingerpiece or linger pieces 31 of reduced diameter to project through avertical guide slot or slots 32 with which one or each side face wall ofthe plug casing is provided.

When the control member 30 is shifted to its normal upward or inwardlimit of its movement relative to the plug casing 10, it is therebymoved between the upper arms 20 of the contact blades 18 and 19, wherebyto rock sai-d blades about their pivoting fulcrums against the tensionof the compression springs 24, thus swinging the contact blades topositions in which they are parallel one to the other, whereby theexternally projecting arms 21 thereof are disposed in straight parallelpositions for Ialignment with, and easy entrance into, the spacedadmission openings of an outlet or other receptacle to which the plug isdesired to be operatively connected (see Fig. 2).

After the plug is inserted in an outlet or receptacle to which it is tobe connected, the control member 30 is manually shifted to its downwardor outward limit of movement, as determined by the guide slots 32 inwhich the nger pieces 31 ride, whereby to align the same with andbetween the pivotal fulcrums of the contact blades 18 and 19 (see Fig.3). When the control member is so positi'oned, it can no longer resistrocking movements of the contact blades about their pivotal fulcrumsunder the thrust of the compression springs 24, and consequently theinserted arms 21 of'the contact blades will be divergently spread, so asto both force the same into good and firm electrical engagement with theinternal contact elements of the outlet or receptacle, While at the sametime thereby serving to obstruct outward withdrawal of said arms 21fromthe outlet or.receptacle,tandthus substantially securing the plugagainst accidental out pulled. disconnection fromsaid outlet orreceptacle.

To. withdraw the plug from an outlet or receptacle to which it isoperatively connected, it is necessary to merely engage the iingerpieces 31 of the control member 30, so that, by pulling the plugoutwardly thereby, the control member 30. will first be moved relativeto the contact blades 13. and 19, whereby to return said blades toparallelism, whereafter continuedy outward pulling of the plug willeasily withdraw the parallelly straightened external arms 21- of theContact blades out of and away from the outlet or receptacle.

From the above, it should now be understood that the instant inventionprovides a very simple and yet easily manipulatable plug connector forassuring both good contact thereof with an outlet or receptacle in whichit is inserted, as well as one substantially guarded against accidentalwithdrawal and separation from the outlet or receptacle.

`Having now described my invention, I claim:

l. A plug connector for an electrical cord comprising a chamberedcasing, a pair of laterally spaced contact blades pivotally mountedintermediate their ends within said casing atpoi'nts adjacent to theouter free end of the latter, said contact blades each having aninternal arm and an external arm outwardly projecting from said casing,compression springs mounted within said casing to eXertyieldably inswinging thrust against said internal arms of the contact blades wherebyto divergently spread the external arms of said contact blades, means tocouple respective electrical cord wires to the ends of the respectiveinternal arms of said contact blades, a control member of substantialiycircular cross section slidably disposed within the casing forlongitudinal movements intermediate and in engagement with the internalarms of the contact blades to and inwardly from an outwardly moved,horizontally aligned position between the pivotal points of said contactblades, whereby, in the latter position, diametrically opposite curvedperipheral surfaces of said control member are opposed to the pivotalpoints of respective contact blades in noneobstructing relation tospring induced rocking movement of said contact blades about theirpivotal points, but, when inwardly moved away from said pivotal points,to rock said blades against spring tension to parallelism, said controlmember having linger engageable means, externally projecting from thecasing, by which the same can be manipulated.

2. A plug connector according to claim 1, wherein the linger engageablemeans of the control member comprises oppositely and horizontallyprojecting finger pieces, and the casingl having slots in opposite facewalls thereof through which said finger pieces respectively project,said slots guiding and limiting the inward and outward movements of thecontrol member.

References Cited in the ile of this patent UNITED STATES PATENTS1,957,773 Good May 8, 1934 2,043,851 Grant June 9, 1936 2,075,632Zuckerman Mar. 30, 1937 2,195,546 Townsend Apr. 2, 1940 2,254,754v ReeceSept. 2, 1941 2,436,586 Mangold Feb. 24, 1948 FOREIGN PATENTS 463,842Great Britain Apr. 7, 1937

